1. Field of the Invention
This invention relates to a method of producing II-V compound semiconductors and more particularly to a method of producing II-V compound semiconductors with greatly reduced density of intrinsic defect levels suitable for use in such electronic devices as solar cells, sensors, lasers, transistors, and diodes.
2. Description of the Prior Art
The electronics industry, which got its start using semiconductors in Group IV of the Periodic Table (Ge, Si), later was able to practically apply II-VI compounds such as CdS, ZnS, ZnO, etc. and today has reached the stage of utilizing III-V compounds such as GaAs, GaP, and InP, etc.
Now II-V compounds have come to show strong promise of constituting the next generation of electronic materials. Among these, zinc phosphide (Zn.sub.3 P.sub.2), the constituent elements of which are known to be present in abundant deposits near the surface of the earth, is drawing particularly strong attention as a material which it is hoped will make it possible to produce highly efficient solar cells, sensors, lasers and the like at low cost.
For the practical application of the II-V compound semiconductors, however, it is necessary to overcome the problems posed by the fact that they are defect semiconductors having several vacancies in their unit cells. Cadmium arsenide, for example, has a pseudofluorite structure wherein the cadmium atom at every fourth lattice site constitutes a vacancy, while in the case of zinc phosphide, 8 vacancies of zinc atoms are involved in the 40 atoms of each unit cell. As a result, these semiconductors include numerous deep defect levels attributed to the deficiency of atoms so that up to now it has been impossible to practically apply them to electronic devices because of their extremely low performance.